Some more virtual/override updates.

mojo/common/handle_watcher_unittest.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "mojo/common/handle_watcher.h"
 
 #include <string>
 
 #include "base/at_exit.h"
 #include "base/auto_reset.h"
@@ skipping 103 matching lines @@
 
   base::WeakPtrFactory<CallbackHelper> weak_factory_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(CallbackHelper);
 };
 
 class HandleWatcherTest : public testing::TestWithParam<MessageLoopConfig> {
  public:
   HandleWatcherTest() : message_loop_(CreateMessageLoop(GetParam())) {}
-  virtual ~HandleWatcherTest() {
+  ~HandleWatcherTest() override {
     test::SetTickClockForTest(NULL);
   }
 
  protected:
   void TearDownMessageLoop() {
     message_loop_.reset();
   }
 
   void InstallTickClock() {
     test::SetTickClockForTest(&tick_clock_);
@@ skipping 323 matching lines @@
                               message_loop.task_runner(),
                               &run_loop, &threads_active_counter));
   }
   run_loop.Run();
   ASSERT_EQ(0, threads_active_counter);
 }
 
 }  // namespace test
 }  // namespace common
 }  // namespace mojo